Low-to-Mid Range Water-Reducing Polymer With Mixed Polyoxyalkylene Side Chains

A method for achieving low-to-mid-range water reduction in a hydratable cementitious composition, comprising:

• combining with water and cement to form a hydratable cementitious mixture, wherein the water-to-cement (w/c) ratio is at least 0.44 and no greater than 0.80, at least one comb-type carboxylate copolymer formed from the following monomer components (A), (B), (C), and optionally (D);
• (A) a first polyoxyalkylene monomer represented by structural formula:
• wherein R1 and R2 individually represent hydrogen atom or methyl group;
• R3 represents hydrogen or —COOM group wherein M represents a hydrogen atom or an alkali metal;
• AO represents oxyalkylene group having 2 to 4 carbon atoms or mixtures thereof;
• “m” represents an integer of 0 to 2;
• “n” represents an integer of 0 or 1;
• “o” represents an integer of 0 to 4;
• “p” represents an average number of oxyalkylene groups and is an integer from 5 to 35;
• and R4 represents a hydrogen atom or C1 to C4 alkyl group;
• (B) a second polyoxyalkylene monomer represented by structural formula:
• wherein R1 and R2 individually represent hydrogen atom or methyl group;
• R3 represents hydrogen or —COOM group wherein M represents a hydrogen atom or an alkali metal;
• AO represents an oxyalkylene group having 2 to 4 carbon atoms or mixtures thereof;
• “m” represents an integer of 0 to 2;
• “n” represents an integer of 0 or 1;
• “o” represents an integer of 0 to 4;
• “q” represents an average number of oxyalkylene groups and is an integer from 20 to 200;
• and R4 represents a hydrogen atom or C1 to C4 alkyl group;
• (C) an unsaturated carboxylic acid monomer represented by structural formula:
• wherein R5 and R6 individually represent hydrogen atom or methyl group;
• R7 represents hydrogen atom, C(O)OR8, or C(O)NHR8 wherein R8 represents a C1 to C4 alkyl group, and M represents a hydrogen atom or an alkali metal;
• and, optionally,
• (D) an unsaturated, water-soluble monomer represented by structural formula:
• wherein R9, R10, and R11 each independently represent a hydrogen atom, methyl group or C(O)OH;
• X represents C(O)NH2, C(O)NHR12, C(O)NR13R14, O—R15, SO3H, C6H4SO3H, or C(O)NHC(CH3)2CH2SO3H, or mixture thereof, wherein R12, R13, R14, and R15 each independently represent a C1 to C5 alkyl group;
• and
• wherein the molar ratio of component (A) to component (B) is from 15:85 to 85:15, and further wherein the molar ratio of component (C) to the sum of component (A) and component (B) is 90:10 to 50:50.